MSX2 and cleidocranial dysplasia 1: Furthermore, other genetic diseases can show a similar phenotype to that of CCD, such as parietal foramina with cleidocranial dysplasia, which results from mutations in Drosophila muscle segment homeobox gene homologue 2 (MSX2) (Garcia-Minaur et al., 2003; Ott et al., 2012).